Release protective film and manufacturing method thereof

Abstract

The invention discloses a release protective film and a manufacturing method thereof. The manufacturing method of the release protective film comprises the following steps: preparing a resin material; the resin material is subjected to a calendering step and a stretching step to form a resin film layer; and using an embossing wheel to form patterned embossing with the depth of 1-5 microns on the resin film layer so as to prepare the release protective film. Wherein the resin material comprises a polyolefin material and petroleum resin. Based on 100 parts by weight of the polyolefin material, the addition amount of the petroleum resin is 5-20 parts by weight. The release protective film can be prepared by a simple process, and has the characteristics of high structural strength and low release force.

Description

Technical Field

[0001] The present application relates to a release protective film and a method for manufacturing the same, and in particular to a release protective film suitable for large-size displays or panels and a method for manufacturing the same. Background Art

[0002] Generally speaking, the protective film needs to have a certain structural strength to achieve sufficient protection. Currently, most of the protective films on the market are made of cast polypropylene (CPP) films by extrusion or blowing.

[0003] However, cast polypropylene film made by extrusion or blowing has a smooth surface and a high release force. When cast polypropylene film is used as a protective film, it cannot be easily separated from the display or panel, which is not conducive to use.

[0004] Therefore, in the prior art, a release layer is coated on the surface of the cast polypropylene film to increase the roughness of the protective film surface, so that the protective film has a lower release force from the display or panel. After use, the protective film can be easily separated from the display or panel. However, in terms of the overall process, the coating process increases the complexity of the process, and the use of solvents is not environmentally friendly.

[0005] Moreover, with the advancement of technology, the size of displays and panels continues to expand. For large-sized (40-inch to 100-inch) displays and panels, the protective film needs to have good adhesion to the display or panel to achieve a protective effect. In addition, the protective film still needs to have a low release force to tear off the protective film from the display or panel.

[0006] Therefore, how to improve material design and manufacturing methods to make the protective film have both good adhesion and low release force to meet the needs of large-size displays and panels on the market has become one of the important issues that this business wants to solve. Summary of the invention

[0007] The technical problem to be solved by the present application is to provide a release protective film and a manufacturing method thereof in view of the deficiencies of the prior art.

[0008] In order to solve the above technical problems, one of the technical solutions adopted in the present application is to provide a method for manufacturing a release protective film. The method for manufacturing a release protective film includes: preparing a resin material; the resin material undergoes a calendering step and a stretching step to form a resin film layer; using an embossing wheel to form a patterned embossing with a depth of 1 micron to 5 microns on the resin film layer to obtain a release protective film. The resin material includes a polyolefin material and a petroleum resin, and the amount of the petroleum resin added is 5 to 20 parts by weight based on 100 parts by weight of the polyolefin material.

[0009] Preferably, the release protective film is completed in a continuous process, and the release protective film is formed in one piece.

[0010] Preferably, the petroleum resin is a hydrogenated petroleum resin.

[0011] Preferably, the petroleum resin is a hydrogenated petroleum resin polymerized with a monomer having 5 carbon atoms or a hydrogenated petroleum resin polymerized with a monomer having 9 carbon atoms.

[0012] Preferably, based on the total weight of the polyolefin material being 100 weight percent, the polyolefin material comprises 15 weight percent to 65 weight percent of the propylene polymer and 35 weight percent to 85 weight percent of the ethylene polymer.

[0013] Preferably, taking the total weight of the polyolefin material as 100 weight percent, the polyolefin material includes 50 weight percent to 70 weight percent of propylene polymer, 10 weight percent to 30 weight percent of ethylene polymer and 10 weight percent to 25 weight percent of ethylene vinyl acetate copolymer.

[0014] Preferably, the resin material is stretched at a ratio of 3.5 to 4.5 in the stretching step.

[0015] Preferably, the depth of the patterned embossing on the resin film layer is 1 micrometer to 3 micrometers.

[0016] In order to solve the above technical problems, another technical solution adopted by the present application is to provide a release protective film, which is made by the above manufacturing method. The release force of the release protective film on the glass surface is 130g / 25mm to 200g / 25mm.

[0017] Preferably, the haze of the release protective film is less than 5.2%.

[0018] One of the beneficial effects of the present application is that the release protective film and the manufacturing method thereof provided in the present application can make the release protective film easily adhered to the glass surface and have an appropriate release force with the glass surface through the technical scheme of "adding 5 to 20 parts by weight of petroleum resin" and "using an embossing wheel to form a patterned embossing with a depth of 1 micron to 5 microns on the resin film layer", so as to overcome the problem that the previous protective film could not be produced with a simple process to have both high structural strength and low release force characteristics.

[0019] To further understand the features and technical contents of the present application, please refer to the following detailed description and drawings of the present application. However, the drawings provided are only for reference and illustration and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a flow chart of a method for manufacturing a release protective film.

[0021] Figure 2 This is a schematic diagram of the release protective film of this application. DETAILED DESCRIPTION

[0022] The following is an explanation of the implementation methods of the "release protective film and its manufacturing method" disclosed in the present invention through specific examples. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed in various ways based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only simple schematic illustrations and are not depicted according to actual dimensions. It is stated in advance. The following embodiments will further explain the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the scope of protection of the present invention. In addition, the term "or" used in this article may include any one or more combinations of the associated listed items depending on the actual situation.

[0023] In order to solve the problem that the conventional protective film manufacturing process is complicated and cannot have both high structural strength and low release force characteristics, the present invention improves the material and manufacturing method for forming the protective film so that the protective film can be applied to large-sized displays and panels in the optoelectronic industry.

[0024] The present invention forms patterned embossing on the surface of the release protective film by using an embossing wheel, thereby achieving the effect of reducing the release force of the release protective film on the glass surface. In addition, the release protective film of the present invention is integrally formed, and can achieve the release effect of being easy to tear off by itself, without the need to set a release layer through a coating step or a laminating step. In addition, the release protective film of the present invention is made in a continuous process system, which has the advantage of a simple process.

[0025] The present invention selects specific materials to make the release protective film, so that the release protective film has the characteristics of high structural strength and low haze.

[0026] By selecting specific materials, the present invention slightly improves the release force of the release protective film on the glass surface. In this way, the release protective film can have better bonding strength with the display and panel while being easy to remove. In other words, the release protective film of the present invention can have good adhesion with a large area of ​​glass substrate, and is thus suitable for large-size (40 inches to 100 inches) displays and panels.

[0027] See also Figure 1 As shown, the method for manufacturing the release protective film of the present invention includes the following steps: preparing a resin material (step S1), the resin material undergoes a calendering step and a stretching step to form a resin film layer (step S2), and an embossing wheel is used to obtain a release protective film (step S3).

[0028] In step S1 , the resin material includes a polyolefin material and a petroleum resin, and the polyolefin material is a main component of the release protective film.

[0029] In an exemplary embodiment, the polyolefin material includes at least a propylene polymer and an ethylene polymer. The addition of petroleum resin can enhance the release force of the release protective film on the glass surface, and the addition of petroleum resin can reduce the haze of the resin material. For actual products, the haze of the release protective film is preferably less than 5.2%.

[0030] Experimental tests have found that when the amount of petroleum resin added is too much, the viscosity of the resin material is too high, which is not conducive to production. When the amount of petroleum resin added is too low, the release force of the release protective film on the glass surface is low.

[0031] Specifically, based on 100 parts by weight of polyolefin material, the amount of petroleum resin added is 5 to 20 parts by weight. For example, the amount of petroleum resin added can be 6 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 14 parts by weight, 16 parts by weight or 18 parts by weight.

[0032] In an exemplary embodiment, the petroleum resin may be a hydrogenated petroleum resin, specifically, a hydrogenated petroleum resin polymerized with a monomer having 5 carbon atoms or a hydrogenated petroleum resin polymerized with a monomer having 9 carbon atoms.

[0033] For example, the petroleum resin may be a hydrogenated piperylene resin or a hydrogenated dicyclopentadiene (DCPD) resin, or a water-white thermoplastic resin obtained by polymerization and hydrogenation of a C9 fraction, a byproduct of ethylene cracking. However, the present invention is not limited thereto.

[0034] The selection of the polyolefin material will also affect the release force of the protective film on the glass surface. In an exemplary embodiment, the polyolefin material includes a propylene polymer and an ethylene polymer.

[0035] The propylene polymer may be a random propylene polymer, a binary copolymer polypropylene (formed by polymerization of propylene monomer and ethylene monomer), a ternary copolymer polypropylene (formed by polymerization of propylene monomer, ethylene monomer and butene monomer) or a propylene block copolymer.

[0036] In a preferred embodiment, random propylene polymer can be selected as the polyolefin material. Random propylene polymer has low crystallinity, which can improve the formation effect of patterned embossing and enhance the exhaust effect of the film surface to avoid bubbles formed between the release protective film and the glass surface.

[0037] Specifically, the melting point of the random propylene polymer is 140 to 150° C., preferably 142 to 146° C. The melt index of the random propylene polymer is 2 to 5, preferably 2 to 4.

[0038] In a preferred embodiment, linear low density polyethylene can be selected as the ethylene polymer. Specifically, the melt index of the linear low density polyethylene is 2 to 5, preferably 2 to 4.

[0039] The present invention further controls the ratio of propylene polymer to ethylene polymer to adjust the hardness of the polyolefin material. Taking the total weight of the polyolefin material as 100 weight percent, the polyolefin material comprises 15 weight percent to 65 weight percent of the propylene polymer and 35 weight percent to 85 weight percent of the ethylene polymer.

[0040] For example, the content of propylene polymer can be 20 weight percent, 30 weight percent, 40 weight percent, 50 weight percent or 60 weight percent. The content of ethylene polymer can be 40 weight percent, 50 weight percent, 60 weight percent, 70 weight percent or 80 weight percent.

[0041] In addition to propylene polymers and ethylene polymers, the polyolefin material may further include ethylene vinyl acetate copolymers.

[0042] The addition of ethylene vinyl acetate copolymer can improve the release force of the release film on the glass surface while facilitating removal, so as to facilitate application in large-size displays or panels.

[0043] However, the content of ethylene vinyl acetate copolymer needs to be controlled within a specific range. When the content of ethylene vinyl acetate copolymer is too high, the viscosity of the resin material is too high and difficult to produce. When the content of ethylene vinyl acetate copolymer is too low, the release force of the release protective film on the glass surface is low and cannot be well attached to the glass surface.

[0044] Therefore, the present invention further controls the proportion of propylene polymer, ethylene polymer and ethylene-vinyl acetate copolymer to adjust the characteristics of the polyolefin material. Taking the total weight of the polyolefin material as 100 weight percent, the polyolefin material includes 50 weight percent to 70 weight percent of propylene polymer, 10 weight percent to 30 weight percent of ethylene polymer and 10 weight percent to 25 weight percent of ethylene-vinyl acetate copolymer. In a preferred embodiment, taking the total weight of the polyolefin material as 100 weight percent, the content of ethylene-vinyl acetate copolymer is 15 weight percent to 20 weight percent.

[0045] By selecting the above materials, the release protective film of the present invention can have both good adhesion and appropriate release force, and can be particularly applied to large-size displays or panels in the optoelectronic industry.

[0046] In the calendering step of step S2, the temperature of the screw is controlled to be 170°C to 240°C to calender the resin material.

[0047] In the stretching step of step S2, the resin material is stretched at a stretching ratio of 3 to 5 times at a temperature of 100° C. to 160° C. to form a resin film layer. Preferably, the resin material is stretched at a stretching ratio of 3.5 to 4.5 times in the stretching step. The stretching ratio of the resin material is preferably 4 times. For example, when the stretching ratio is 5 times, the rigidity of the resin film layer increases, but the release force decreases.

[0048] In step S3, by using an embossing wheel, a patterned embossing with a depth of 1 to 5 microns can be formed on the resin film layer to produce a release protective film. Preferably, the depth of the patterned embossing on the resin film layer is 1 to 3 microns.

[0049] In an exemplary embodiment, the pattern on the embossing wheel is a diamond shape, and the pattern depth of the diamond shape is 0.5 mm to 1.5 mm, and preferably the pattern depth is 0.75 mm to 1.25 mm.

[0050] Specifically, the above steps S1 to S3 are completed in a continuous process. Therefore, the method for manufacturing the release protective film of the present invention has the advantage of a simple process. In addition, the manufactured release protective film is integrally formed.

[0051] See also Figure 2 As shown, a patterned embossing 11 is formed on the attachment surface 10 of the release protective film 1. The groove pattern of the patterned embossing 11 corresponds to the convex pattern on the embossing wheel. In this way, the contact surface area of ​​the release protective film when it is set on the glass substrate can be reduced, so as to achieve the effect of reducing the release force of the release protective film on the glass substrate.

[0052] In addition, in order to control the release force between the release protective film and the glass substrate, the depth of the patterned embossing on the resin film layer can be adjusted. As for the embossing pattern, diamond embossing is preferred, but the present invention is not limited thereto, and other quadrilateral embossing patterns can also be used.

[0053] [Examples 1 to 4]

[0054] In order to verify that the release protective film of the present invention can be attached to a glass substrate and has an appropriate release force, according to the above steps S1 to S3, random propylene polymer and low-density polyethylene are selected as polyolefin materials, and hydrogenated petroleum resin and polyolefin materials are mixed to prepare resin materials.

[0055] After the resin material is subjected to the calendering step and the stretching step, a resin film layer is formed. The resin film layer is passed through an embossing wheel to form patterned embossing on the surface of the resin film layer to obtain the release protective films of Examples 1 to 4. The thickness of the release protective films in Examples 1 to 4 is 100 μm to 150 μm. However, the thickness of the release protective film is not limited thereto, and the thickness can be adjusted according to the size of the display or panel.

[0056] Next, the haze and release force of the release protective film were measured, and the adhesion of the release protective film to the glass substrate was evaluated. The specific component content of the resin material, the stretching ratio in the stretching step, the depth of the patterned embossing, and the characteristic evaluation results of the release protective film are listed in Table 1.

[0057] The haze of the release film is measured according to the ASTM D1003 (CIE C) standard established by the American Society for Testing and Materials (ASTM).

[0058] In the measurement of release force, a roller weighing 4.5 pounds is used to roll the release film back and forth once, so that the release film adheres to the glass surface. Then, the glass is fixed to the lower clamp, the release film is folded back and fixed to the upper clamp, and the release film and the glass are torn apart at 180 degrees in the opposite direction at a rate of 30 mm / min. The average peeling force during the process is taken as the release force.

[0059] In the evaluation of adhesion, the adhesion of the release protective film on the glass substrate is divided into three levels. In Table 1, when the release protective film is easily adhered to the glass substrate, it is indicated as "good", when the release protective film is easily adhered to the glass substrate but is easily wrinkled or unevenly adhered, it is indicated as "acceptable", and when the release protective film is not easily adhered to the glass substrate, it is indicated as "poor".

[0060] [Examples 5 to 6]

[0061] The release protective films of Examples 5 to 6 are similar to the release protective films of Examples 1 to 4, except that the polyolefin material further includes ethylene vinyl acetate copolymer in addition to the random propylene polymer and the low-density polyethylene.

[0062] After the resin material is prepared according to the component contents in Table 1, the resin material is subjected to a calendering step and a stretching step to form a resin film layer. The resin film layer is then processed by an embossing wheel to form a patterned embossing on the surface of the resin film layer, and a release protective film is prepared. The haze and release force of the release protective film are also measured, and the adhesion of the release protective film to the glass substrate is evaluated. The specific component contents of the resin material, the stretching ratio in the stretching step, the depth of the patterned embossing, and the characteristic evaluation results of the release protective film are listed in Table 1.

[0063] [Comparative Example 1]

[0064] The release protective film of Comparative Example 1 is similar to the release protective film of Example 1, except that hydrogenated petroleum resin is not added to the resin material, and patterned embossing is not formed on the surface of the release protective film.

[0065] After the resin material is prepared according to the component contents in Table 1, the resin material is subjected to a calendering step and a stretching step to form a resin film layer. The resin film layer is not processed by an embossing wheel, and a release protective film is directly prepared. The haze and release force of the release protective film are also measured, and the adhesion of the release protective film to the glass substrate is evaluated. The specific component contents of the resin material, the stretching ratio in the stretching step, the depth of the patterned embossing, and the characteristic evaluation results of the release protective film are listed in Table 1.

[0066] [Comparative Example 2]

[0067] The release protective film of Comparative Example 2 is similar to the release protective film of Example 1, except that hydrogenated petroleum resin is not added to the resin material.

[0068] After the resin material is prepared according to the component contents in Table 1, the resin material is subjected to a calendering step and a stretching step to form a resin film layer. The resin film layer is then processed by an embossing wheel to form a patterned embossing on the surface of the resin film layer, and a release protective film is prepared. The haze and release force of the release protective film are also measured, and the adhesion of the release protective film to the glass substrate is evaluated. The specific component contents of the resin material, the stretching ratio in the stretching step, the depth of the patterned embossing, and the characteristic evaluation results of the release protective film are listed in Table 1.

[0069] Table 1

[0070]

[0071]

[0072] According to the results in Table 1, the release protective film of the present invention has an appropriate release force (120 g / 25 mm to 200 g / 25 mm), can be smoothly attached to the glass substrate, and is easy to tear off. Specifically, the release force of the release protective film is greater than 120 g / 25 mm. In order to facilitate tearing, the release force of the release protective film needs to be less than 200 g / 25 mm.

[0073] In addition, the results of Examples 5 and 6 show that when the polyolefin material includes propylene polymer, ethylene polymer and ethylene-vinyl acetate copolymer, the release force of the release film is 150 g / 25 mm to 200 g / 25 mm. Thus, the release film of the present invention can be applied to large-size (40-inch to 100-inch) displays or panels.

[0074] According to the results in Table 1, the addition of petroleum resin can increase the release force of the release protective film on the glass surface to higher than 120g / 25mm, and even higher than 145g / 25mm. In addition, the addition of petroleum resin can reduce the haze of the resin material to less than 5.2%.

[0075] From the results of Examples 1 and 2, it can be seen that too large a stretch ratio will reduce the release force of the release protective film. After experimental testing, the optimal stretch ratio is 3 to 5 times, which can make the release force of the release protective film on the glass surface higher than 145g / 25mm.

[0076] From the results of Examples 1, 3 and 4, it can be seen that the content ratio of the polyolefin material will affect the haze and release force of the release protective film, and can be adjusted according to demand within the content range.

[0077] It can be seen from the results of Examples 5 and 6 that the depth of the patterned embossing will also affect the release force of the release protective film. After experimental testing, the depth of the patterned embossing is preferably 1 micron to 3 microns.

[0078] It is worth noting that the release protective film of the present invention is manufactured by continuous process and does not need to be coated or laminated to form a release layer on the surface of the release protective film, which has the advantages of simple process and environmental friendliness.

[0079] [Beneficial Effects of Embodiments]

[0080] One of the beneficial effects of the present invention is that the release protective film and the manufacturing method thereof provided by the present invention can make the release protective film easily adhered to the glass surface and have an appropriate release force with the glass surface through the technical scheme of "adding 5 to 20 parts by weight of petroleum resin" and "using an embossing wheel to form a patterned embossing with a depth of 1 micron to 5 microns on the resin film layer", thereby overcoming the difficulty that the previous protective film could not be made with a simple process to have both high structural strength and low release force characteristics.

[0081] Furthermore, the content of the polyolefin material will also affect the release force of the release film. When the polyolefin material is added with propylene polymer, ethylene polymer and ethylene vinyl acetate copolymer, the release force of the release film can be improved while facilitating the removal of the release film, so that the release film can be used for large-sized displays or panels.

[0082] In addition, the content ratio of propylene polymer, ethylene polymer and ethylene vinyl acetate copolymer will also affect the release force of the release protective film. When the content of ethylene vinyl acetate copolymer is too high, the viscosity of the resin material is too high and it is difficult to produce. When the content of ethylene vinyl acetate copolymer is too low, the release force of the release protective film on the glass surface is low and it cannot adhere well to the glass surface.

[0083] The contents disclosed above are only preferred feasible embodiments of the present application, and are not intended to limit the protection scope of the claims of the present application. Therefore, all equivalent technical changes made using the contents of the present application specification and drawings are included in the protection scope of the claims of the present application.

Claims

1. A method for manufacturing a release protective film, characterized in that: The manufacturing method comprises: Preparing a resin material, wherein the resin material comprises a polyolefin material and a petroleum resin, and based on 100 parts by weight of the polyolefin material, the addition amount of the petroleum resin is 5 parts by weight to 20 parts by weight; The resin material is subjected to a calendering step and a stretching step to form a resin film layer; and An embossing wheel is used to form patterned embossing with a depth of 1 micrometer to 5 micrometers on the resin film layer to prepare a release protective film.

2. The method for manufacturing a release protective film according to claim 1, characterized in that: The release protective film is completed in a continuous process, and the release protective film is formed in one piece.

3. The method for manufacturing a release protective film according to claim 1, characterized in that: The petroleum resin is hydrogenated petroleum resin.

4. The method for manufacturing a release protective film according to claim 3, characterized in that: The petroleum resin is a hydrogenated petroleum resin polymerized with a monomer having 5 carbon atoms or a hydrogenated petroleum resin polymerized with a monomer having 9 carbon atoms.

5. The method for manufacturing a release protective film according to claim 1, characterized in that: Taking the total weight of the polyolefin material as 100 weight percent, the polyolefin material includes 15 weight percent to 65 weight percent of the propylene polymer and 35 weight percent to 85 weight percent of the ethylene polymer.

6. The method for manufacturing a release protective film according to claim 1, characterized in that: Taking the total weight of the polyolefin material as 100 weight percent, the polyolefin material includes 50 weight percent to 70 weight percent of propylene polymer, 10 weight percent to 30 weight percent of ethylene polymer and 10 weight percent to 25 weight percent of ethylene vinyl acetate copolymer.

7. The method for manufacturing a release protective film according to claim 1, characterized in that: The resin material is stretched at a ratio of 3.5 to 4.5 in the stretching step.

8. The method for manufacturing a release protective film according to claim 1, characterized in that: The depth of the patterned embossing on the resin film layer is 1 micron to 3 microns.

9. A release protective film, characterized in that: The release protective film is made by the method for making a release protective film according to any one of claims 1 to 8, and the release force of the release protective film on the glass surface is 130 g / 25 mm to 200 g / 25 mm.

10. The release protective film according to claim 9, characterized in that: The haze of the release protective film is less than 5.2%.

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